The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses a transponder key ecu that stores the key codes of authorized ignition keys. If an attempt is made to start the engine using an unauthorized key, the ecu sends a signal to the ecm to prohibit fuel delivery and ignition, effectively disabling the engine.

The transponder key coil receives this signal, the transponder key amplifier amplifies it, and then the signal is transmitted to the ecu. The ecu matches the key's id code with the vehicle's id code, which was previously registered in the ecu and then communicates the results to the ecm using sfi communication.
Engine immobiliser system
How to proceed with troubleshootingInstallation (2005/11-2006/01)
Install front drive shaft assembly lh
Coat the spline of the inboard joint shaft with gear
oil.
Using a brass bar and hammer, align the shaft
splines in the drive shaft.
Notice:
Set the snap ring with the opening side facing
downwards.
Be careful not to damage the oil s ...
Brake warning light does not come on
Wiring diagram
Refer to the brake warning light circuit (see page bc-145).
Inspection procedure
Check can communication system
Check if the can communication system dtc is output
(see page ca-34).
Result
Perform active test by intelligent tester (brake warning light)
...
On-vehicle inspection
Check front seat side airbag assembly (vehicle not involved in
collision)
Perform a diagnostic system check (see page rs-
49).
With the front seat side airbag installed on the
vehicle, perform a visual check. If any of the defects
mentioned below are present, replace the fron ...